The present invention relates to an adjustable, tamper-proof energy absorption device that can be used in all types of applications where it is necessary to absorb shock or control motion between two members movable relative to one another. Such devices are typically used to decelerate and control moving loads and mechanisms in equipment such as robotic assembly machines, packaging machinery, and automated storage and retrieval systems.
When an original equipment manufacturer (OEM) installs an absorption device in a particular piece of equipment, it is necessary that the device have damping characteristics that are specifically suited for the particular equipment application. For example, a shock absorber used to decelerate a small, light-weight pallet on a conveyor system would have different damping characteristics than a shock absorber used to decelerate a large, heavy pallet on a larger conveyor system.
Conventional absorption devices are known wherein the damping setting of the device is preset at the factory for a particular application. No adjustment by the OEM is possible. This makes it impossible to mass produce a "generic" absorption device that can be selectively tuned by an OEM for various different equipment applications.
Other conventional absorption devices have been known that enable the OEM to adjust the damping setting of the absorption device during installation, and then lock the damping setting at the desired setting.
Adjustable absorption devices have also been known wherein the OEM can adjust the damping setting of the device to suit the needs of a particular equipment application. U.S. Pat. Nos. 4,709,791 and 5,598,904, owned by the same assignee as the present application, disclose such an absorption device. However, the end user of the equipment can also adjust the damping setting of the absorption device, thus resulting in the possibility that the device later will be misadjusted for a particular application to the point where the absorption characteristics of the absorption device are ineffective for the particular application.